Context. Understanding large-scale mass exchange in binaries also requires studies of complicated objects in the rapid phases of the process. β Lyr is one such object. Aims. Our goals were to analyse 52 photographic and 651 electronic spectra of β Lyr to obtain additional information about circumstellar matter and to investigate spectrophotometric information for the first time. Methods. Improved quadratic ephemeris was derived via orbital solution with the FOTEL program. The spectra were disentangled using the KOREL program. Spectrophotometric quantities of 15 stronger absorption lines of the primary were measured and corrected for the orbital continuum variations using the fluxes calculated from a fit of the light curves with the BINSYN program. Central intensities of the V and R peaks of the Hα emission line were measured and corrected for the orbital light changes using the R-band light curve numerically modelled with the program PERIOD04. Results. Disentangling of photographic and electronic spectra led to the detection of weak absorption lines originating from the pseudophotosphere of the accretion disc. This way, a rich line spectrum of the accretion disc, not limited to only two previously known Si ii 6347 and Si ii 6371 lines, was obtained. A projected rotational velocity of 180 km s −1 was estimated for the disc spectrum. Such a value agrees well with the assumption of the Keplerian rotation of the outer layers of the accretion disc. After the correction, a pronounced increase of the strength of all absorption lines around phases of the primary eclipse was found. We argue that this is due to additional absorption of the light of the primary in one of the jets and/or scattering envelope above the accretion disc of the gainer. The net intensity of the V peak of Hα shows no orbital variation, but a possible 271-d periodicity. The net intensity of the R peak shows mild orbital changes and a slow change over a cycle of about 2780 days. These results seem to support the earlier conclusion that the Hα emission originates in the jet-like structures. Conclusions. All new findings support the current picture that the circumstellar structures of β Lyr consist of a thick accretion disc, bipolar jets, and a scattering envelope above the disc.

Analysis of eclipsing binaries containing non-radial pulsators allows i) combining two different and independent sources of information on the internal structure and evolutionary status of the components and ii) studying the effects of tidal forces on pulsations. KIC 3858884 is a bright Kepler target whose light curve shows deep eclipses, complex pulsation patterns with pulsation frequencies typical of δ Sct, and a highly eccentric orbit. We present the result of the analysis of Kepler photometry and of high resolution phaseresolved spectroscopy. Spectroscopy yielded both the radial velocity curves and, after spectral disentangling, the primary-component effective temperature and metallicity, and line-of-sight projected rotational velocities. The Kepler light curve was analyzed with an iterative procedure that was devised to disentangle eclipses from pulsations and takes the visibility of the pulsating star into account during eclipses. The search for the best set of binary parameters was performed by combining the synthetic light curve models with a genetic minimization algorithm, which yielded a robust and accurate determination of the system parameters. The binary components have very similar masses (1.88 and 1.86 M ) and effective temperatures (6800 and 6600 K), but different radii (3.45 and 3.05 R ). The comparison with the theoretical models showed a somewhat different evolutionary status of the components and the need to introduce overshooting in the models. The pulsation analysis indicates the hybrid nature of the pulsating (secondary) component, where the corresponding high order g-modes might be excited by an intrinsic mechanism or by tidal forces.

Abstract.We present an analysis of new spectroscopic observations of the bright Be star κ Dra obtained at the Ondřejov observatory during 1992−2003 and UBV photometric observations secured at several observatories. General characteristics and a line identification of the spectrum of κ Dra are obtained in the regions 3730−5650 Å and 5850−7800 Å by a comparison with the theoretical spectrum. The fundamental stellar parameters have been obtained from a comparison with a grid of NLTE model atmospheres. The best fit was found for T eff = 14 000 K, log g = 3.5, and v sin i = 170 km s −1 . These values together with a Hipparcos parallax lead to a stellar mass M = 4.8 ± 0.8 M and radius R = 6.4 ± 0.5 R . It is encouraging to see that these values agree well with the expected evolutionary mass and radius for the effective temperature we derived. Long-term variations of κ Dra were analysed using measurements of equivalent widths, central intensities, peak intensities of emission lines and emission peak velocity differences for Hα, Hβ, Hγ, Hδ, and some helium, silicon, and iron lines. The previously reported period of 23 years in the variation of the emission strength is probably a cyclic, not a strictly periodic phenomenon. An attempt to find out a period from all available records of the Hβ emission strength led to a value of (8044 ± 167) days (22.0 years) but the phase plots show that each cycle has a different shape and length. The maximum strength of the emission lags behind the brightness maximum. This is a behaviour usually observed for long-term changes of Be stars with a positive correlation between the brightness and emission strength. Since there are obviously no published speckle observations of the star, we suggest these should be carried out. They could help to deny or confirm the possibility that the emission episodes are triggered by a periastron passage of a putative binary companion moving in an eccentric orbit with a 8044-d period, as it seems to be the case for some Be binaries. For the moment, the nature and origin of the disk around κ Dra remains unknown. From the comparison of the electronic spectra obtained at different phases of the long-term cycle and synthetic spectra it appears that there are no detectable changes in the photospheric part of the Balmer lines related to variations in the Balmer emission strength which could be attributed to an extended photosphere corresponding to inner parts of the disk, optically thick in continuum.

The Kepler mission has yielded a large number of planet candidates from among the Kepler Objects of Interest (KOIs), but spectroscopic follow-up of these relatively faint stars is a serious bottleneck in confirming and characterizing these systems. We present motivation and survey design for an ongoing project with the Sloan Digital Sky Survey III multiplexed Apache Point Observatory Galactic Evolution Experiment (APOGEE) near-infrared spectrograph to monitor hundreds of KOI host stars. We report some of our first results using representative targets from our sample, which include current planet candidates that we find to be false positives, as well as candidates listed as false positives that we do not find to be spectroscopic binaries. With this survey, KOI hosts are observed over ∼20 epochs at a radial velocity (RV) precision of 100-200 m s −1 . These observations can easily identify a majority of false positives caused by physically associated stellar or substellar binaries, and in many cases, fully characterize their orbits. We demonstrate that APOGEE is capable of achieving RV precision at the 100-200 m s −1 level over long time baselines, and that APOGEE's multiplexing capability makes it substantially more efficient at identifying false positives due to binaries than other single-object spectrographs working to confirm KOIs as planets. These APOGEE RVs enable ancillary science projects, such as studies of fundamental stellar astrophysics or intrinsically rare substellar companions. The coadded APOGEE spectra can be used to derive stellar properties (T eff , g log ) and chemical abundances of over a dozen elements to probe correlations of planet properties with individual elemental abundances.